services: dhcp-client: Better track dhclient's PID.

* gnu/services/networking.scm (dhcp-client-service)[start]: Remove
  PID-FILE first.  When 'call-with-input-file' throws ENOENT, try
  again.
This commit is contained in:
Ludovic Courtès 2015-05-09 22:28:03 +02:00
parent 54d6223d2c
commit c217cbd84d
1 changed files with 15 additions and 1 deletions

View File

@ -165,6 +165,8 @@ Protocol (DHCP) client, on all the non-loopback network interfaces."
(provision '(networking))
(start #~(lambda _
(false-if-exception (delete-file #$pid-file))
;; When invoked without any arguments, 'dhclient'
;; discovers all non-loopback interfaces *that are
;; up*. However, the relevant interfaces are
@ -178,7 +180,19 @@ Protocol (DHCP) client, on all the non-loopback network interfaces."
"-pf" #$pid-file
ifaces))))
(and (zero? (cdr (waitpid pid)))
(call-with-input-file #$pid-file read)))))
(let loop ()
(catch 'system-error
(lambda ()
(call-with-input-file #$pid-file read))
(lambda args
;; 'dhclient' returned before PID-FILE
;; was created, so try again.
(let ((errno (system-error-errno args)))
(if (= ENOENT errno)
(begin
(sleep 1)
(loop))
(apply throw args))))))))))
(stop #~(make-kill-destructor))))))
(define %ntp-servers